PRESIDENT’S ADDRESS. 735 
finally disappears under the Post-Tertiary deposits of the Lodden 
Valley, and covers the ancient river-courses which trend towards 
the Murray River.* 
Allowing for the previous depression during the Miocene and 
Kocene epochs, and an antecedent greater depression during the 
formation of the Victorian carbonaceous beds, there must still 
have been a continuous land surface of mountainous country far 
back into pre-Friassic, if not into Upper Paleozoic, time. During 
all that vast extent of geological time the rivers had been eroding 
their valleys in the higher parts of central-western Victoria, which 
in the upper volcanic era of the Pleiocene epoch were sealed up and 
levelled off by flows of basaltic lavas. 
As seen in the Ballarat district, flows of basalt followed 
each other, separated by periods of time which permitted the 
accumulation of alluviums, until finally vast areas became basaltic 
plains, studded with volcanic cones. t 
The older dividing range is in many parts covered, and the 
newer river-courses do not in places accord with the older drainage 
areas. 
Thus were formed what are known to miners as the deep leads, 
trending from Ballarat northwards towards the river Murray, 
and southwards towards Bass’s Strait. 
It is not possible in the present state of information to fix with 
any degree of accuracy when in geological time these deep leads 
were formed, when volcanic activity was greatest, or when it 
finally terminated with the voleanoes of south-western Victoria, 
and the south-east of South Australia. 
These latter are placed by Professor Tatet in that time when 
Diprotodon, Phascolomys Pliocenus, were still existing, and when 
the flora included Casuarina and Banksia. 
The late discoveries of bones of Macropus Anak and other 
extinct kangaroos in the mine of the Great Buninyong Estate 
Company, to which I have more fully referred elsewhere,§ 
probably places the voleanoes of Mount Buninyong in the same 
time, and this can scarcely be placed further back than the later 
Pleiocene, if so far. This, however, I do merely as an approxima- 
tion to the time when the Pleiocene rivers of central Victoria were 
sealed up by the basalts of the newer volcanic era, and thus 
formed certain of the deep leads of Victoria. 
More recent marine formations of somewhat limited extent 
occur in Victoria, and elsewhere on either side of Bass’s Strait, 
the position of which appears to indicate a comparatively slight 
downwards oscillation, followed by a still slighter upward move- 
ment, which, so far as I am able to form an opinion from the 
* xu, p. 117. + XLU, p. 129. t LV, p. Ixix. § See pp. 741, 752, &c. 
